2010-06-21 00:00:00.000

SELECT dateadd(ms,0,DATEADD(dd, DATEDIFF(dd,0,getdate()), 0))

 

2010-06-21 23:59:59.997

SELECT dateadd(ms,-3,DATEADD(dd, DATEDIFF(dd,-1,getdate()), 0))

 

 

ms步频是3

 

当月第一天

 

SELECT DATEADD(mm, DATEDIFF(mm,0,getdate()), 0)

 

当月最后一天

SELECT   dateadd(ms,-3,DATEADD(mm,   DATEDIFF(m,0,getdate())+1,   0))